Sixth seed Andy Roddick was sent packing by South African Kevin Anderson 6-4, 7-5 in the first round of the men's draw at the China Open on Monday after an unavailing series of last gasp match point saves.
"I didn't serve very well. It was unacceptable," Roddick told a tense post-match news conference.
The 29-year-old American then snapped at a Chinese reporter who asked him if he was considering retiring.
"I think you should retire," he said before abruptly leaving the media room.
World number one Caroline Wozniacki faired better in her first round match, repulsing a tenacious challenge from Lucie Hradecka to open the defence of her China Open title with a 3-6, 6-0, 7-5 first round victory.
The top-seeded Dane struggled to find her rhythm against the powerful Czech's serve in the first set and was forced into a fight for survival in a nail-biting decider against the world number 49.
"It wasn't a pretty match, but I'm through," she said.
"She's a player that doesn't give you any rhythm. She's serving at 200 kilometres per hour, so when it's on, it's difficult.
"But in the second set, her first serve percentage dropped, and that made it easier for me to start the rallies."
The 21-year-old, who was crowned world number one at this event a year ago but who has struggled for form recently, said maintaining her top ranking was paramount.
"If you've been number one pretty much the whole year, you want to finish there as well. It would be a little bit bitter to lose it in the last week of the season," she said.
"So definitely, I just give it my all in the last few tournaments."
Austria's Tamira Paszek became the first woman to reach the third round when she overcame Petra Cetkovska of the Czech Republic 1-6, 6-4, 6-2.
In the men's draw, Germany's Florian Mayer beat Albert Ramos 6-2, 6-4 and Croat Marin Cilic trounced China's Wu Di 6-2, 6-0.
Roddick's exit has left the tournament low on crowd-pulling names after French Open champion and local favourite Li Na's shock first round loss on Sunday and the withdrawal of several top players, including world number two Maria Sharapova.
Defending men's champion and world number one Novak Djokovic pulled out two days before the start of the tournament because of a back injury.